Block polymer compound, polymer composition containing the same, image forming method and image forming apparatus utilizing the same

ABSTRACT

The invention provides a block polymer compound enabling satisfactory dispersion of a colorant in a solvent, and an ink composition containing such block polymer compound. The block polymer compound of the invention is a block polymer compound having at least three block segments, comprising block segments A, B and C arranged in succession, wherein the block segment C is most solvent attractive while the block segment A is most solvent repulsive, and at least either one of the block segments includes an ionic group or an acidic group.

TECHNICAL FIELD

The present invention relates to a novel block polymer compound usefulas various functional materials, a polymer-containing compositioncontaining the same, and an image forming method and an image formingapparatus utilizing the same.

BACKGROUND ART

In the field of aqueous dispersion including a functional material,there are known functional materials, for example, agriculturalchemicals such as a herbicide or an insecticide, pharmaceuticals such asan anticancer agent, an antiallergy agent or an anti-inflammation agent,a coloring material such as an ink or a toner containing a colorant.Recently, digital printing technologies are showing remarkableprogresses. Such digital printing technologies, represented by so-calledelectrophotographic technology and ink jet recording technology, arebecoming more and more important as an image forming technology in theoffices and at homes.

Among such technologies, the ink jet technology, being a directrecording technology, has significant features of compactness and a lowelectric power consumption. Also it recently shows a rapid improvementin the image quality due, for example, to a formation of finer nozzles.An example of the ink jet technology is a method of heating an ink,supplied from an ink tank, with a heater in a nozzle, thereby inducingan evaporation and a bubble formation, thus discharging the ink andforming a record on a recording medium. Another example is a method ofgenerating a vibration in a piezoelectric element, thereby dischargingthe ink.

The ink employed in these methods is generally an aqueous solution of adye, and hence there may take place a bleeding when plural colors aresuperposed or so-called feathering phenomenon, along a direction offibers of paper in a recorded portion of the recording medium. Foravoiding these drawbacks, U.S. Pat. No. 5,085,698 discloses a use of anink composed of a pigment dispersion. However, there are in fact desiredvarious improvements on such existing technologies.

DISCLOSURE OF THE INVENTION

In consideration of the drawbacks in the known background art, thepresent invention is to provide a block polymer compound which enablessatisfactory dispersion of a functional material in a solvent.

Also the present invention is to provide a polymer-containingcomposition, including the aforementioned block polymer compound andbeing satisfactory in dispersibility, fixability and environmentalaffinity.

The present invention is to provide a block polymer compound having atleast three block segments, comprising block segments A, B and Carranged in succession, wherein the block segment C is most solventattractive while the block segment A is most solvent repulsive, and atleast either one of the block segments has an ionic group or an acidicgroup.

The present invention is to provide a block polymer compound having atleast three block segments, comprising block segments A, B and Carranged in succession, wherein at least either one of the blocksegments has at least a functional group selected from the groupconsisting of a carboxylic acid, a carboxylic acid ester and acarboxylic acid salt, connected to the main chain via two or more atoms.

The present invention is to provide a block polymer compound having atleast three block segments, comprising block segments A, B and Carranged in succession, wherein the block segment A is a hydrophobicblock segment, the block segment B is a nonionic hydrophilic blocksegment, and the block segment C has at least one functional groupselected from the group consisting of a carboxylic acid, a carboxylicacid ester and a carboxylic acid salt.

The present invention is also to provide a polymer-containingcomposition comprising a block polymer compound, a solvent or adispersion medium, and a functional material, wherein the block polymercompound comprises block segments A, B and C arranged in succession, theblock segment C is most solvent attractive while the block segment A ismost solvent repulsive, and at least either one of the block segmentshas an ionic group or an acidic group.

The present invention is also to provide a method of increasing theviscosity of a polymer-containing composition which comprises a blockpolymer compound, a solvent or a dispersion medium, and a functionalmaterial, wherein the block polymer compound comprises block segments A,B and C arranged in succession, the block segment C is most solventattractive while the block segment A is most solvent repulsive, and atleast either one of the block segments has an ionic group or an acidicgroup, the method comprising a step of bringing the composition intocontact with hydrogen ions or metal cations thereby increasing theviscosity of the composition.

The present invention is also to provide an image forming methodcomprising the step of applying an ink onto a recording medium toconduct recording, wherein the ink is a polymer-containing compositioncomprising a block polymer compound, a solvent or a dispersion medium,and a functional material, wherein the block polymer compound comprisesblock segments A, B and C arranged in succession, the block segment C ismost solvent attractive while the block segment A is most solventrepulsive, and at least either one of the block segments has an ionicgroup or an acidic group.

The present invention is also to provide an image forming apparatus forconducting recording by applying an ink onto a recording medium, whereinthe ink is a polymer-containing composition comprising a block polymercompound, a solvent or a dispersion medium, and a functional material,wherein the block polymer compound comprises block segments A, B and Carranged in succession, the block segment C is most solvent attractivewhile the block segment A is most solvent repulsive, and at least eitherone of the block segments has an ionic group or an acidic group.

According to the present invention, there can be provided a blockpolymer compound capable of satisfactorily dispersing a functionalmaterial into a solvent.

Also according to the present invention, such block polymer compound canbe utilized to provide a polymer-containing composition and an inkcomposition satisfactory in dispersibility, fixability, andenvironmental affinity.

Also according to the present invention, such composition can beutilized to provide an image forming method and an image formingapparatus satisfactory in dispersibility, fixability and environmentalaffinity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an example of a configuration of anink jet recording apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

The present inventors have made the present invention as a result ofintensive investigations.

In the present invention, a first invention is a block polymer compoundhaving at least three block segments, comprising block segments A, B andC arranged in succession, wherein the block segment C is most solventattractive while the block segment A is most solvent repulsive, and atleast either one of the block segments has an ionic group or an acidicgroup.

More specifically, in the present invention, the block segments A, B andC arranged in succession are solvent attractive in the order of A<B<C,and A or C is substantially ionic. As an ionic functional group, thereis preferred a carboxylic acid or a carboxylic acid salt, and there canbe employed an ordinarily employed organic acid or a salt thereof, anordinarily employed organic base or a salt thereof. The block segments,having such successively varying property and showing an ioniccharacter, allow to exhibit a more uniform micelle structure.

In the block polymer compound, it is preferred that C is mosthydrophilic and A is most hydrophobic.

In the present invention, a second invention is a block polymer compoundhaving at least three block segments, comprising block segments A, B andC arranged in succession, wherein at least either one of the blocksegments has at least a functional group selected from the groupconsisting of a carboxylic acid, a carboxylic acid ester and acarboxylic acid salt, connected to a main chain via two or more atoms.

In the foregoing, “at least one selected from the group consisting of acarboxyl acid, a carboxylic acid ester and a carboxylic acid salt,connected to a main chain via two or more atoms” means that a carboxylacid, a carboxylic acid ester or a carboxylic acid salt is not presentin a form directly connected to the main chain but connected through acertain connecting group that has two or more atoms. More specifically,the carboxylic acid, the carboxylic acid ester or the carboxylic acidsalt is not present in such a form that the mobility thereof isrestricted by the main chain as in a polymer of acrylic acid,methacrylic acid, itaconic acid or a derivative thereof, but in such aform that the carboxylic acid, carboxylic acid ester or carboxylic acidsalt is capable of a certain free molecular movement via a connectinggroup such as an alkylene group or an alkyleneoxy group. Consequentlythe connecting group has two or more atoms, preferably three or moreatoms, more preferably four or more atoms and further preferably five ormore atoms.

This is because a connected structure too close to the main chain mayrestrict mobility of carboxylic acid, carboxylic acid ester orcarboxylic acid salt thereby possibly hindering an intermolecular orintramolecular interaction. Therefore, a structure of a free carboxylicacid or of a carboxylic acid salt is preferred for fully attaining suchinteraction. However, such free carboxylic acid or carboxylic acid saltis often obtained by hydrolyzing a carboxylic acid ester. Therefore, acarboxylic acid ester structure is very useful as a synthesis precursorfor a free carboxylic acid structure or a carboxylic acid saltstructure, though it may not be able to exert much intermolecular orintramolecular interaction.

In the present invention, a third invention is a block polymer compoundhaving at least three block segments, comprising block segments A, B andC arranged in succession, wherein the block segment A is a hydrophobicblock segment, the block segment B is a nonionic hydrophilic blocksegment, and the block segment C has at least one functional groupselected from the group consisting of a carboxylic acid, a carboxylicacid ester and a carboxylic acid salt. The block segments of suchsequence and structures have successively varying properties and anionic character, thereby enabling to exhibit a more uniform micellestructure. Free carboxylic acid or carboxylic acid salt is oftenobtained by hydrolyzing a carboxylic acid ester. Therefore, a carboxylicacid ester structure is very useful as a synthesis precursor for a freecarboxylic acid structure or a carboxylic acid salt structure, though itmay not be able to exert much intermolecular or intramolecularinteraction.

The block polymer compound of the present invention is a block polymercompound have three or more block segments. Examples of the blockstructure are as follows. The present invention includes a triblockpolymer having mutually different block segments ABC, and a structure inwhich another polymer unit is bonded to such triblock structure. Forexample, the present invention includes a structure having fourdifferent block segments ABCD, a structure of ABCA, and a block polymerhaving an even larger number of block segments. The block polymer of thepresent invention is characterized by including at least three blocksegments.

The block polymer used in the present invention is also called a blockcopolymer.

In a preferred embodiment, the block polymer compound of the presentinvention is an amphiphilic polymer compound. Such amphiphilic characteris exhibited by that, in the block polymer compound of the presentinvention, at least a block segment is solvent attractive while at leastanother block segment is solvent repulsive. Such solvent attractivecharacter and solvent repulsive character are preferably exhibited withrespect to an aqueous solvent. Stated differently, the block polymer ofthe present invention preferably includes at least a hydrophobic segmentand at least a hydrophilic segment.

A preferred specific example of the block polymer compound of thepresent invention is a compound including a polyvinyl ether structure asa repeating unit structure. Also there is preferred a compound includinga repeating unit structure which has a carboxylic acid, a carboxylicacid ester or a carboxylic acid salt in a side chain and is representedby the following general formula (1):

wherein R⁰ represents —X— (COOH)_(r), —X— (COOR¹⁰)_(r), or—X—(COO-M)_(r); X represents a linear, branched or cyclic alkylene groupwith 1 to 20 carbon atoms, —(CH(R⁵)—CH(R⁶)—O)_(p)—(CH₂)_(m)—CH_(3-r)—,—(CH₂)_(m)—(O)_(n)—(CH₂)_(q)—CH_(3-r)— or a structure in which at leastone of methylene groups therein is replaced by a carbonyl group or anaromatic ring structure; r represents 1 or 2; p represents an integerfrom 1 to 18; m represents an integer from 0 to 35, n represents 1 or 0;q represents an integer from 0 to 17; R¹⁰ represents an alkyl group; Mrepresents a monovalent or polyvalent cation; and R⁵ and R⁶, which maybe the same or different, each independently represent an alkyl group.

In the following, there will be shown specific examples of the repeatingunit structure represented by the general formula (1):

In the foregoing, Ph represents a phenylene group.

A preferred specific example of the compound having a polyvinyl etherstructure is a compound including a repeating unit represented by thefollowing general formula (2):

In the foregoing general formula, R¹ is a group selected from the groupconsisting of a linear, branched or cyclic alkyl group with 1 to 18carbon atoms, -Ph, -Pyr, -Ph-Ph, -Ph-Pyr, —(CH(R⁵)—CH(R⁶)—O)_(p)—R⁷ and—(CH₂)_(m)—(O)_(n)—R⁷, in which a hydrogen atom in an aromatic ring maybe replaced by a linear or branched alkyl group with 1 to 4 carbon atomsand a carbon atom in an aromatic ring may be replaced by a nitrogenatom;

p represents an integer from 1 to 18; m represents an integer from 1 to36; n represents 0 or 1;

R⁵ and R⁶ each independently represent a hydrogen atom or —CH₃;

R⁷ represents a hydrogen atom, a linear, branched or cyclic alkyl groupwith 1 to 18 carbon atoms, -Ph, -Pyr, -Ph-Ph, -Ph-Pyr, —CHO, —CH₂CHO,—CO—CH═CH₂, —CO—C(CH₃)═CH₂, or —CH₂COOR⁸, in which, in case R⁷ is otherthan a hydrogen atom, a hydrogen atom bonded to a carbon atom in R⁷ maybe replaced by a linear or branched alkyl group with 1 to 4 carbonatoms, —F, —Cl or —Br while a carbon atom in an aromatic ring may bereplaced by a nitrogen atom; R⁸ represents a hydrogen atom or an alkylgroup with 1 to 5 carbon atoms; Ph represents a phenyl group; and Pyrrepresents a pyridyl group.

Specific examples of the repeating unit structure represented by thegeneral formula (2) include the following:

wherein Ph represents a phenylene group.

The block polymer compound of the present invention is preferably ablock polymer having three or more block segments including ahydrophobic block segment and a hydrophilic block segment and alsoincluding at least one stimulus-responsive block segment. A specificexample is an ABC triblock polymer, including a hydrophobic blocksegment A represented by:

as an example of the aforementioned hydrophobic repeating unit, also asegment B represented by:

as an example of the aforementioned stimulus-responsive repeating unit,and a segment C represented by:

as an example of the aforementioned repeating unit.

In the block polymer compound of the present invention, each blocksegment may be constituted of a single repeating unit or of a structureof plural repeating units. Examples of the block segment constituted ofplural repeating units include a random copolymer and a graduationcopolymer in which a composition ratio shows a gradual change.

Also the block polymer compound of the present invention is a blockpolymer having three or more block segments, and can also be a polymerin which such block polymer is grafted to another polymer.

In the present invention, the content of the repeating unit structurerepresented by the general formula (1) in the block polymer compound iswithin a range from 0.01 to 99 mol. % with respect to the entire blockpolymer compound, preferably 1 to 90 mol. %. A content less than 0.01mol. % may result in an insufficient polymer interaction to be exertedby carboxylic acid, carboxylic acid ester or carboxylic acid salt, whilea content exceeding 99 mol. % may result in an excessive interaction,thus leading to an insufficient function.

The block polymer compound of the present invention has a number-averagemolecular weight (Mn) within a range from 200 to 10,000,000, preferably1,000 to 1,000,000. A molecular weight exceeding 10,000,000 may resultin an excessive entanglement within a polymer chain or between polymerchains, thus leading to a difficulty in dispersion in the solvent. Onthe other hand, a molecular weight less than 200 may result in adifficulty in exhibiting a steric effect as a polymer, because of anexcessively low molecular weight. In each block segment, a preferreddegree of polymerization is from 3 to 10,000, more preferably 5 to 5,000and further preferably 10 to 4,000.

For improving a dispersion stability and an inclusivity, the blockpolymer preferably has a more flexible molecular mobility. This isbecause a more flexible molecular mobility of the block polymer enhancesa physical entanglement of the block polymer with the surface of afunctional material, thereby increasing affinity. Also such flexiblecharacter is preferred also in forming a coating layer on a recordingmedium as will be explained later. For this end, the main chain of theblock polymer preferably has a glass transition temperature Tg of 20° C.or less, more preferably 0° C. or less and further preferably −20° C. orless. Also in this regard, a polymer having a polyvinyl ether structurecan be employed advantageously since it generally has a low glasstransition point and is flexible. Most of the aforementioned repeatingunit structures have a glass transition temperature of about −20° C. orlower.

The block polymer compound having the polyvinyl ether repeating unitstructure and advantageously employed in the present invention is oftenpolymerized by a cationic polymerization. As an initiator, there can beemployed a combination of a protonic acid such as hydrochloric acid,sulfuric acid, methanesulfonic acid, trifluoroacetic acid,trifluoromethanesulfonic acid or perchloric acid, or a Lewis acid suchas BF₃, AlCl₃, TiCl₄, SnCl₄, FeCl₃, RAlCl₂ or R_(1.5)AlCl_(1.5) (Rrepresenting an alkyl group) and a cation source (which can be aprotonic acid, water, an alcohol or an addition product of vinyl etherand a carboxylic acid). Such initiator is made to be present with apolymerizable compound (monomer) whereby a polymerization reactionproceeds and the block polymer compound can be synthesized. In the blockpolymer compound including the polyvinyl ether repeating unit structureand preferably employed in the present invention, the polyvinyl etherrepeating unit structure is more preferably contained in a content of 90mol. % or higher.

In the following there will be explained a polymerization method morepreferably employed in the present invention. Various methods have beenreported for synthesizing a polymer including a polyvinyl etherstructure (cf. Japanese Patent Application Laid-open No. 11-080221),among which representative ones are a method by a cation livingpolymerization by Aoshima et al. (Polymer Bulletin, vol. 15, 1986, p.417; Japanese Patent Application Laid-open Nos. 11-322942 and11-322866). A polymer synthesis by cation living polymerization allowsto obtain various polymers such as a homopolymer, a copolymer composedof two or more monomer components, a block polymer, a graft polymer or agraduation polymer, with an exactly aligned length (molecular weight).The living polymerization can also be executed in an HI/I₂ system or inan HCl/SnCl₄ system.

The block polymer compound of the present invention, comprising blocksegments including a repeating unit structure having a carboxylic acid,a carboxylic acid ester or a carboxylic acid salt which is not directlyconnected to a main chain of the polymer but is connected via aconnecting group with two or more atoms, can exhibit an interactionsuitable for forming a high-order structure or a highly stabledispersion. Also, including three segments of successively varyingsolvent attractive property and having three or more block segments canexhibit three or more functions. Therefore, in comparison with a polymercompound including two or less block segments, it can also form aprecise structured member of a higher order. It is also possible, byproviding the plural block segments with similar properties, tostabilize the properties of the polymer.

In the following there will be explained a fourth invention of thepresent invention.

In the present invention, a fourth invention is a polymer-containingcomposition which comprises a solvent or a dispersion medium, afunctional material and the aforementioned block polymer compound of thepresent invention. The composition may include the aforementioned blockpolymer compound and a functional material for exerting a predetermineduseful function such as a colorant, and such block polymer compound canbe advantageously utilized for satisfactorily dispersing the functionalmaterial or the like. The functional material is preferably a liquid ora solid, and may be a soluble substance. For example there can beemployed an oil, a pigment, a metal, a herbicide, an insecticide, amaterial derived from a living organism, a pharmaceutical, a dye or amolecular catalyst.

In the polymer-containing composition of the present invention, theblock polymer compound of the present invention is contained in anamount of 0.1 to 99 mass % with respect to the weight of thecomposition, preferably 0.3 to 70 mass %. A content less than 0.1 mass %may result in an insufficient dispersibility for the functionalmaterial, while a content exceeding 99 mass % may result in anexcessively high viscosity. Also in the composition of the presentinvention, the functional material is contained in an amount of 0.1 to80 mass %, preferably 0.5 to 60 mass %. A content less than 0.1 mass %may result in an insufficient functionality while a content exceeding 80mass % may cause an insufficient dispersion.

Further, the polymer-containing composition of the present inventionincludes a solvent or a dispersion medium, and a binder resin may beemployed as the dispersion medium. For the solvent or the dispersionmedium, there can be employed water, an aqueous solvent or a non-aqueousorganic solvent, or they may be employed as a mixture.

Examples of the aqueous solvent include a polyhydric alcohol such asethylene glycol, diethylene glycol, triethylene glycol, polyethyleneglycol, propylene glycol, popypropylene glycol, or glycerin; apolyhydric alcohol ether such as ethylene glycol monomethyl ether,ethylene glycol monoethyl ether, ethylene glycol monobutyl ether,diethylene glycol monoethyl ether or diethylene glycol monobutyl ether;and a nitrogen-containing solvent such as N-methyl-2-pyrrolidone, asubstituted pyrrolidone, or triethanol amine. There can also be employeda monohydric alcohol such as methanol, ethanol, or isopropyl alcohol.

Examples of a non-aqueous organic solvent include a hydrocarbon solventsuch as hexane, heptane, octane, decane or toluene; cyclohexanone,acetone, methyl ethyl ketone and butyl acetate. There can also beemployed a natural oil or fat such as olive oil, soy bean oil, beeftallow or lard.

Examples of the binder resin include a styrene-acryl copolymer andpolyester.

In the polymer-containing composition of the present invention, thesolvent or the dispersion medium is contained in an amount of 1 to 99mass %, preferably 10 to 95 mass %. A content less than 1 mass % orexceeding 99 mass % may result in an insufficient dispersion of thefunctional material.

The polymer-containing composition of the present invention may contain,in addition to the aforementioned components, other components such asan ultraviolet absorber, an antioxidant, a stabilizer etc.

In the polymer-containing composition of the present invention, there isemployed a block polymer compound according to the first invention ofthe present invention, a block polymer compound according to the secondinvention of the present invention, or a block polymer compoundaccording to the third invention of the present invention. For thisreason, it is possible to form an elaborate structure of a higher order.

It is also possible to provide the plural block segments with similarproperties, thereby further stabilizing such property. For example, incase of preparing a dispersion by employing the aforementioned ABC-typetriblock polymer, a colorant and water as the solvent, it is possible toinclude the colorant in a micelle formed by the ABC triblock polymer,thereby obtaining an ink composition of a colorant inclusion type. It isfurthermore possible to obtain a very uniform particle size in suchdispersion, and to obtain an extremely stable dispersion state.

Inclusion of the colorant in the micelle formed by the ABC block polymermeans that the colorant is included in a core portion of the formedmicelle and is dispersed in this state in a solution.

The inclusion state can be realized by mixing a solution or a dispersionof a colorant in a water-immiscible organic solvent utilizing a mixer orthe like for inclusion into the micelles formed by the block polymer inwater, and then distilling off the organic solvent.

It can also be realized by executing a phase transfer of a solution ofboth the polymer and the colorant in an organic solvent into an aqueoussolvent thereby forming an included state, and then distilling off theorganic solvent. It can further be realized by executing a phasetransfer of a mixture containing the dissolved polymer and the dispersedcolorant in an organic solvent into an aqueous solvent thereby formingan included state.

The inclusion state can be confirmed by various analytical methods suchas with an electron microscope or with X-ray diffraction. Also aninclusion state in micelles can be indirectly confirmed by a separationof the colorant and the polymer from the solvent under a micelledestructing condition.

In the present invention, the functional material is preferably in aninclusion state by 90% or higher.

In the following there will be explained an ink composition, which is apreferred embodiment of the composition of the present invention.

In the ink composition of the present invention, the block polymercompound of the present invention is contained within a range from 0.1to 90 mass %, preferably 0.3 to 80 mass %. For use in an ink jetprinter, the content is preferably within a range from 0.3 to 30 mass %.

In the following, there will be given a detailed explanation oncomponents, other than the block polymer compound, to be included in theink composition of the present invention. Such other components includewater, an aqueous solvent, a colorant, an additive etc. Examples ofthese components are the same as the examples explained in theforegoing.

A colorant can representatively be a pigment or a dye. The pigment canbe an organic pigment or an inorganic pigment, and, for use in the ink,there can be advantageously employed a black pigment and pigments ofthree primary colors of cyan, magenta and yellow. It is also possible toemploy pigments of other colors than those explained in the foregoing, acolorless or pale-colored pigment or a metallic luster pigment. In thepresent invention, the pigment to be employed may be commerciallyavailable or newly synthesized. It is also possible to employ a pigmentin combination with a dye.

In the following, there will be shown examples of commercially availablepigments of black, cyan, magenta and yellow colors.

Examples of the black pigment include Raven 1060, Raven 1080, Raven1170, Raven 1200, Raven 1250, Raven 1255, Raven 1500, Raven 2000, Raven3500, Raven 5250, Raven 5750, Raven 7000, Raven 5000 ULTRAII, Raven 1190ULTRAII (foregoing manufactured by Columbian Carbon Inc.), Black PearlsL, MOGUL-L, Regal 1400R, Regal 1660R, Regal 1330R, Monarch 800, Monarch880, Monarch 900, Monarch 1000, Monarch 1300, Monarch 1400 (foregoingmanufactured by Cabot Corp.), Color Black FW1, Color Black FW2, ColorBlack FW200, Color Black 18, Color Black S160, Color Black S170, SpecialBlack 4, Special Black 4A, Special Black 6, Printex 35, Printex U,Printex 140U, Printex V, Printex 140V (foregoing manufactured by DegussaCorp.), No. 25, No. 33, No. 40, No. 47, No. 52, No. 900, No. 2300,MCF-88, MA600, MA7, MA8, and MA10 (foregoing manufactured by MitsubishiChemicals Ltd.), but such examples are not restrictive.

Examples of the cyan color pigment include C.I. Pigment Blue-1, C.I.Pigment Blue-2, C.I. Pigment Blue-3, C.I. Pigment Blue-15, C.I. PigmentBlue-15:2, C.I. Pigment Blue-15:3, C.I. Pigment Blue-15:4, C.I. PigmentBlue-16, C.I. Pigment Blue-22 and C.I. Pigment Blue-60, but theseexamples are not restrictive.

Examples of the magenta color pigment include C.I. Pigment Red-5, C.I.Pigment Red-7, C.I. Pigment Red-12, C.I. Pigment Red-48, C.I. PigmentRed-48:1, C.I. Pigment Red-57, C.I. Pigment Red-112, C.I. PigmentRed-122, C.I. Pigment Red-123, C.I. Pigment Red-146, C.I. PigmentRed-168, C.I. Pigment Red-184, C.I. Pigment Red-202, and C.I. PigmentRed-207, but these examples are not restrictive.

Examples of the yellow color pigment include C.I. Pigment Yellow-12,C.I. Pigment Yellow-13, C.I. Pigment Yellow-14, C.I. Pigment Yellow-16,C.I. Pigment Yellow-17, C.I. Pigment Yellow-74, C.I. Pigment Yellow-83,C.I. Pigment Yellow-93, C.I. Pigment Yellow-95, C.I. Pigment Yellow-97,C.I. Pigment Yellow-98, C.I. Pigment Yellow-114, C.I. PigmentYellow-128, C.I. Pigment Yellow-129, C.I. Pigment Yellow-151, and C.I.Pigment Yellow-154, but these examples are not restrictive.

In the ink composition of the present invention, there can also beemployed a pigment which is self dispersible in water. Suchwater-dispersible pigment includes one formed by adsorbing a polymer onthe surface of a pigment and utilizing a steric hindrance effect and oneutilizing an electrostatic repulsive force, and commercially availableexamples include CAB-0-JET200, CAB-0-JET300 (foregoing manufactured byCabot Corp.) and Microjet Black CW-1 (manufactured by Orient ChemicalsCo.).

In the ink composition of the present invention, the pigment ispreferably contained within a range of 0.1 to 50 mass % with respect tothe entire weight of the ink composition. A pigment content less than0.1 mass % cannot provide a sufficient image density, while a pigmentcontent exceeding 50 mass % results in a coagulation of the pigment,thus becoming impossible to disperse. A more preferred range is from 0.5to 30 mass %.

A dye can also be employed in the ink composition of the presentinvention. As shown in the following, there can be employed a directdye, an acidic dye, a basic dye, a reactive dye, a water-soluble fooddye or an insoluble dispersion dye.

Examples of the water-soluble dye include:

a direct dye such as C.I. Direct Black-17, -19, -22, -32, -38, -51, -62,-71, -108, -146, -154; C.I. Direct Yellow-12, -24, -26, -44, -86, -87,-98, -100, -130, -142; C.I. Direct Red-1, -4, -13, -17, -23, -28, -31,-62, -79, -81, -83, -89, -227, -240, -242, -243; C.I. Direct Blue-6,-22, -25, -71, -78, -86, -90, -106, -199; C.I. Direct Orange-34, -39,-44, -46, -60; C.I. Direct Violet-47, -48; C.I. Direct Brown-109; andC.I. Direct Green-59;

an acidic dye such as C.I. Acid Black-2, -7, -24, -26, -31, -52, -63,-112, -118, -168, -172, -208; C.I. Acid Yellow-11, -17, -23, -25, -29,-42, -49, -61, -71; C.I. Acid Red-1, -6, -8, -32, -37, -51, -52, -80,-85, -87, -92, -94, -115, -180, -254, -256, -289, -315, -317; C.I. AcidBlue-9, -22, -40, -59, -93, -102, -104, -113, -117, -120, -167, -229,-234, -254; C.I. Acid Orange-7, -19; and C.I. Acid Violet-49;

a reactive dye such as C.I. Reactive Black-1, -5, -8, -13, -14, -23,-31, -34, -39; C.I. Reactive Yellow-2, -3, -13, -15, -17, -18, -23, -24,-37, -42, -57, -58, -64, -75, -76, -77, -79, -81, -84, -85, -87, -88,-91, -92, -93, -95, -102, -111, -115, -116, -130, -131, -132, -133,-135, -137, -139, -140, -142, -143, -144, -145, -146, -147, -148, -151,-162, -163; C.I. Reactive Red-3, -13, -16, -21, -22, -23, -24, -29, -31,-33, -35, -45, -49, -55, -63, -85, -106, -109, -111, -112, -113, -114,-118, -126, -128, -130, -131, -141, -151, -170, -171, -174, -176, -177,-183, -184, -186, -187, -188, -190, -193, -194, -195, -196, -200, -201,-202, -204, -206, -218, -221; C.I. Reactive Blue-2, -3, -5, -8, -10,-13, -14, -15, -18, -19, -21, -25, -27, -28, -38, -39, -40, -41, -49,-52, -63, -71, -72, -74, -75, -77, -78, -79, -89, -100, -101, -104,-105, -119, -122, -147, -158, -160, -162, -166, -169, -170, -171, -172,-173, -174, -176, -179, -184, -190, -191, -194, -195, -198, -204, -211,-216, -217; C.I. Reactive Orange-5, -7, -11, -12, -13, -15, -16, -35,-45, -46, -56, -62, -70, -72, -74, -82, -84, -87, -91, -92, -93, -95,-97, -99; C.I. Reactive Violet-1, -4, -5, -6, -22, -24, -33, -36, -38;C.I. Reactive Green-5, -8, -12, -15, -19, -23; C.I. Reactive Brown-2,-7, -8, -9, -11, -16, -17, -18, -21, -24, -26, -31, -32 and -33;

C.I. Basic Black-2; C.I. Basic Red-1, -2, -9, -12, -13, -14, -27; C.I.Basic Blue-1, -3, -5, -7, -9, -24, -25, -26, -28, -29; C.I. BasicViolet-7, -14, 27; C.I. Food Black-1 and -2.

In the following, there will be shown examples of commercially availableoil-soluble dyes of different colors.

Examples of a black oil-soluble dye include C.I. Solvent Black-3, -5,-6, -7, -8, -13, -22, -22:1, -23, -26, -27, -28, -29, -33, -34, -35,-39, -40, -41, -42, -43, -45, -46, -47, -48, -49, and -50, but theseexamples are not restrictive.

Examples of a yellow oil-soluble dye include C.I. Solvent Yellow-1, -2,-3, -4, -6, -7, -8, -10, -12, -13, -14, -16, -18, -19, -21, -25, -25:1,-28, -29, -30, -32, -33, -34, -36, -37, -38, -40, -42, -43, -44, -47,-48, -55, -56, -58, -60, -62, -64, -65, -72, -73, -77, -79, -81, -82,-83, -83:1, -85, -88, -89, -93, -94, -96, -98, -103, -104, -105, -107,-109, -112, -114, -116, -117, -122, -123, -124, -128, -129, -130, -131,-133, -134, -135, -138, -139, -140, -141, -143, -146, -147, -148, -149,-150, -151-, -152, -153, -157, -158, -159, -160:1, -161, -162, -163,-164, -165, -167, -168, -169, -170, -171, and -172, but these examplesare not restrictive.

Examples of an orange oil-soluble dye include C.I. Solvent Orange-1, -2,-3, -4, -4:1, -5, -6, -7, -11, -16, -17, -19, -20, -23, -25, -31, -32,-37, -37:1, -38, -40, -40:1, -41, -45, -54, -56, -59, -60, -62, -63,-67, -68, -71, -72, -73, -74, -75, -76, -77, -79, -80, -81, -84, -85,-86, -91, -94, -95, -98, and 99, but these examples are not restrictive.

Examples of a red oil-soluble dye include C.I. Solvent Red-1, -2, -3,-4, -7, -8, -13, -14, -17, -18, -19, -23, -24, -25, -26, -27, -29, -30,-33, -35, -37, -39, -41, -42, -43, -45, -46, -47, -48, -49, -49:1, -52,-68, -69, -72, -73, -74, -80, -81, -82, -83, -83:1, -84, -84:1, -89,-90, -90:1, -91, -92, -106, -109, -111, -117, -118, -119, -122, -124,-125, -127, -130, -132, -135, -138, -140, -143, -145, -146, -149, -150,-151, -152, -155, -160, -164, -165, -166, -168, -169, -172, -175, -176,-177, -179, -180, -181, -182, -185, -188, -189, -195, -198, -202, -203,-204, -205, -206, -207, -208, -209, -210, -212, -213, -214, -215, -216,-217, -218, -219, -220, -221, -222, -223, -224, -225, -226, -227, -228and -229, but these examples are not restrictive.

Examples of a violet oil-soluble dye include C.I. Solvent Violet-2, -3,-8, -9, -10, -11, -13, -14, -21, -21:1, -24, -31, -32, -33, -34, -36,-37, -38, -45, -46, and -47, but these examples are not restrictive.

Examples of a blue oil-soluble dye include C.I. Solvent Blue-2, -4, -5,-7, -10, -11, -12, -14, -22, -25, -26, -35, -36, -37, -38, -43, -44,-45, -48, -49, -50, -51, -59, -63, -64, -66, -67, -68, -70, -72, -79,-81, -83, -91, -94, -95, -97, -98, -99, -100, -102, -104, -105, -111,-112, -116, -117, -118, -122, -127, -128, -129, -130, -131, -132, -133,and -134, but these examples are not restrictive.

Examples of a green oil-soluble dye include C.I. Solvent Green-1, -3,-4, -5, -7, -8, -9, -20, -26, -28, -29, -30, -32 and -33, but theseexamples are not restrictive.

Examples of a brown oil-soluble dye include C.I. Solvent Brown-1, -1:1,-2, -3, -4, -5, -6, -12, -19, -20, -22, -25, -28, -29, -31, -37, -38,-42, -43, -44, -48, -49, -52, -53 and -58, but these examples are notrestrictive.

In the ink composition of the present invention, the dye is preferablyemployed in an amount of 0.1 to 50 mass % with respect to the entireweight of the ink. The aforementioned examples of the colorants arepreferred to the ink composition of the present invention, but thecolorant to be employed in the ink composition of the present inventionis not limited to those shown in the foregoing.

For the solvent, there can be employed water, an aqueous solvent or anorganic solvent, but water is preferably employed. As the water, thereis preferred ion-exchanged water, purified water or ultra purified waterin which metal ions etc. are eliminated.

In the ink composition of the present invention, water is containedpreferably within a range from 1 to 95 mass %, more preferably within arange from 5 mass % to less than 95 mass %. Within such range from 1 to95 mass %, the effect of dispersion is more enhanced and the functionalmaterial can be dispersed in a more uniform state.

Examples of the aqueous solvent include a polyhydric alcohol such asethylene glycol, diethylene glycol, triethylene glycol, polyethyleneglycol, propylene glycol, polypropylene glycol, or glycerin; apolyhydric alcohol ether such as ethylene glycol monomethyl ether,ethylene glycol monoethyl ether, ethylene glycol monobutyl ether,diethylene glycol monoethyl ether or diethylene glycol monobutyl ether;and a nitrogen-containing solvent such as N-methyl-2-pyrrolidone, asubstituted pyrrolidone, or triethanol amine. Also for expediting dryingon paper (recording medium) in the use of the ink, there can be employeda monohydric alcohol such as methanol, ethanol or isopropyl alcohol.

In the ink composition of the present invention, the aqueous solvent ispreferably contained in an amount of 0.1 to 50 mass %, more preferably0.5 to 40 mass %. Within such range from 0.1 to 50 mass %, the wettingeffect is more enhanced and the functional material can be dispersed ina more uniform state.

In the ink composition of the present invention, the aforementionedblock polymer compound is contained within a range of 0.1 to 90 mass %with respect to the entire weight, preferably 0.3 to 80 mass %. Acontent of the block polymer less than 0.1 mass % may make it impossibleto sufficiently disperse the pigment contained in the ink composition ofthe present invention, while a content exceeding 90 mass % may cause anexcessively high viscosity.

In the present invention, a fifth invention is a method of increasingthe viscosity of the composition of the aforementioned fourth inventionby bringing it in contact with hydrogen ions or metal cations. Morespecifically, the present invention provides a method of increasing theviscosity of a composition which includes the block polymer compound ofthe present invention and the functional material which are typicallyformed into micelles in an aqueous solution by bringing such compositioninto contact with hydrogen ions or polyvalent metal ions (for example,cations of zinc, aluminum, calcium, barium, nickel etc.) thereby causinga coagulation of the micelle particles. Since the employed polymer isfor example a carboxylic acid salt and in an ionized state, such ionicfunctional group is neutralized by contact with a sufficient amount ofhydrogen ions or metal cations, whereby the affinity between themicelles increases rapidly and the viscosity significantly increases atthe same time. Such method can be advantageously applied to an inkcomposition.

The contact with the composition of the present invention can beattained, for example, by a method of contact with a solution ofhydrogen ions or polyvalent metal cations, or a method of contact with amedium which is coated in advance with hydrogen ions or polyvalent metalcations. The amount of contact or addition is within a range from 0.01to 100 mol.eq. with respect to the ionic groups of the polymer,preferably 0.05 to 50 mol.eq.

In addition, the ink composition may have a responsiveness to astimulus. Based on such stimulus-responsiveness, it is possible toincrease the viscosity of the ink, by giving a stimulus in the course ofan image formation, thereby providing a satisfactory fixing ability.Such stimulus may be suitably selected from a change in temperature, anexposure to an electromagnetic wave, a pH change, and a change inconcentration, or may be a combination thereof, in consideration ofmatching with the image forming process.

A preferred embodiment of the present invention is an ink composition ofwhich characteristics is variable in response to a stimulus, and whichcan be utilized as a pigment dispersion ink, showing a high dispersionstability of the pigment and capable of improving a bleeding or afeathering phenomenon when applied on a recording medium and furtherexcellent in a fixing ability and a friction resistance. Therefore theink composition for the pigment dispersion ink of the present inventioncan be utilized as an image forming material of a high image quality, alow energy consumption and a high recording speed.

The polymer-containing composition of the present invention can be madeto change its state (characteristics) in response to various stimuli.Examples of the “stimulus” in the present invention include a change intemperature, an application of an electric field, an exposure to a light(electromagnetic wave) such as ultraviolet, visible or infrared light, apH change in the composition, an addition of a chemical substance, and achange in the concentration of the composition.

The ink composition of the present invention can be advantageouslyutilized as an ink for ink jet recording.

In the following, there will be explained a method for preparing an inkjet ink of the present invention.

(Method for Preparing Ink for Ink Jet)

An ink composition of the present invention for ink jet recording can beprepared, for example, by adding a pigment, a block polymer compound ofthe present invention, an additive etc., into ion-exchanged water, thenexecuting a dispersion by a dispersing equipment, eliminating coarseparticles, for example, by a centrifuge, then adding water or a solventand an additive etc., followed by agitation, mixing and filtration.

The dispersing equipment can be, for example, an ultrasonic homogenizer,a laboratory homogenizer, a colloid mill, a jet mill or a ball mill,which may be utilized singly or in combination.

Also in case of employing a self-dispersible pigment, an ink compositioncan be prepared in a similar manner as explained in the foregoing.

In the following there will be explained a liquid application method ofthe present invention.

(Liquid Application Method)

The ink composition of the present invention is employed, in a preferredembodiment, in a liquid application method for ejecting an ink from anink ejecting unit for application on a recording medium, therebyconducting a recording. It is preferably employed in a pattern formingmethod for forming a predetermined pattern on a recording medium, or invarious image forming methods such as various printing methods, an inkjet method or an electrophotographic method for forming an image or acharacter on a recording medium, and particularly preferably employed inan ink jet method.

Such ink jet method can be a piezoelectric ink jet method utilizing apiezoelectric element or a thermal ink jet method for effectingrecording by a bubble formation under an application of thermal energy.Also such ink jet method can be of the continuous type or on-demandtype. Further, the ink composition of the present invention can beutilized in a recording method in which ink is printed on anintermediate transfer member and then transferred onto a final recordingmedium such as a paper.

In the following, an image forming apparatus of the present inventionwill be explained.

(Liquid Application Apparatus)

The ink composition of the present invention can be utilized in a liquidapplication apparatus employing the aforementioned liquid applicationmethod, a pattern forming apparatus employing a pattern forming methodfor forming a predetermined pattern on a recording medium, or an imageforming apparatus utilizing various image forming methods such asvarious printing methods, an ink jet method or an electrophotographicmethod for forming an image or a character on a recording medium, andparticularly employed in an ink jet recording apparatus.

An ink jet recording apparatus utilizing the ink jet ink of the presentinvention includes a piezo ink jet method employing a piezoelectricelement and a thermal ink jet method for effecting recording by a bubbleformation under an application of thermal energy.

FIG. 1 is a schematic functional view of an ink jet recording apparatus.A numeral 50 denotes a central processing unit (CPU) of an ink jetrecording apparatus 20. A program for controlling the CPU 50 may bestored in a program memory 66, or as so-called firmware in memory meanssuch as an EEPROM (not shown). The ink jet recording apparatus receivesrecording data from recording data preparation means (such as a computernot shown), into the program memory 66. The recording data may beinformation of an image or a character to be recorded, information in acompressed form, or encoded information. In case of compressed orencoded information, the CPU 50 is caused to execute an expanding ordeveloping process to obtain the information of the image or thecharacter to be recorded. An X-encoder 62 (for an X-direction or a mainscanning direction) and a Y-encoder 64 (for a Y-direction or a subscanning direction) are provided to inform the CPU 50 with a relativeposition of a recording head relative to a recording medium.

The CPU 50, based on the information from the program memory 66, theX-encoder 62 and the Y-encoder 64, sends signals for image recording toan X-motor drive circuit 52, a Y-motor drive circuit 54 and a head drivecircuit 60. The X-motor drive circuit 52 and the Y-motor drive circuit54 respectively drive an X-direction drive motor 56 and a Y-directiondrive motor 58 thereby moving the recording head 70, relative to therecording medium, to a recording position. When the head 70 is moved tothe recording position, the head drive circuit 60 provides the head 70with signals for causing ejections of the ink compositions (C, M, Y, K)or a stimulus-giving material for causing a stimulus, thereby achievingrecording operation. The head 70 may be so constructed as to eject anink composition of a single color, or plural ink compositions, and mayalso be provided with a function of ejecting a stimulus providingmaterial for causing a stimulus.

EXAMPLES

In the following the present invention will be further clarified byexamples, but the present invention is not limited to such examples.

Example 1

<Synthesis of Block Polymer>

Synthesis of a triblock polymer constituted of isobutyl vinyl ether(IBVE: A block), 2-methoxyethyl vinyl ether (MOVE: B-block) and ethyl4-(2-vinyloxy)ethoxybenzoate (VEOEtPhCOOEt: C block):

The interior of a glass container equipped with a three-way stopcock wasreplaced with nitrogen, and adsorbed water was eliminated by heating at250° C. under a nitrogen flow. After the system was returned to the roomtemperature, 12 mmol of IBVE, 16 mmol of ethyl acetate, 0.05 mmol of1-isobutoxyethyl acetate and 11 ml of toluene were added and thereaction system was cooled. When the temperature in the system reached0° C., polymerization was initiated by adding 0.2 mmol of ethyl aluminumsesquichloride (equimolar mixture of diethyl aluminum chloride and ethylaluminum dichloride). Completion of polymerization of the A block wasconfirmed by monitoring the molecular weight at intervals with a gelpermeation chromatography (GPC).

Then, polymerization was continued by adding 12 mmol of MOVEconstituting the B block. After completion of polymerization of the Bblock was confirmed by monitoring with GPC, the polymerization wascontinued by adding a toluene solution of 10 mmol of the C blockcomponent. The polymerization reaction was terminated after 20 hours.The termination of the polymerization was achieved by adding a 0.3 mass% ammonia/methanol aqueous solution. The reaction mixture was dilutedwith dichloromethane, and was washed three times with 0.6 M hydrochloricacid and three times with distilled water. The obtained organic phasewas concentrated and dried in an evaporator, then dried under vacuum andwas subjected to repeated dialyses with a cellulose semi-permeatingmembrane and in methanol for eliminating monomer compounds, therebyobtaining a desired triblock polymer. The compound was identified by NMRand GPC, and had Mn=40,482, Mw/Mn=1.36, and a polymerization ratioA:B:C=200:200:30.

The block polymer obtained above was subjected to a hydrolysis in amixture of dimethylformamide and an aqueous sodium hydroxide solution toobtain a triblock polymer in which the C block was hydrolyzed andconverted into a sodium salt. The compound was identified by NMR andGPC.

It was further neutralized in an aqueous dispersion with 0.1 Nhydrochloric acid to obtain a triblock polymer in which the C componentwas converted into a free carboxylic acid. The compound was identifiedby NMR and GPC.

Example 2

Synthesis of a triblock polymer constituted of isobutyl vinyl ether andCH₂═CHOCH₂CH₂OPhPh (IBVE-r-VEEtPhPh: A block), 2-ethoxyethyl vinyl ether(EOVE: B-block) and ethyl 4-(2-vinyloxy)ethoxybenzoate (C block):

The interior of a glass container equipped with a three-way stopcock wasreplaced with nitrogen, and adsorbed water was eliminated by heating at250° C. under a nitrogen flow. After the system was returned to the roomtemperature, 6 mmol of IBVE, 6 mmol of VEEtPhPh, 16 mmol of ethylacetate, 0.1 mmol of 1-isobutoxyethyl acetate and 11 ml of toluene wereadded and the reaction system was cooled. When the temperature in thesystem reached 0° C., polymerization was initiated by adding 0.2 mmol ofethyl aluminum sesquichloride (equimolar mixture of diethyl aluminumchloride and ethyl aluminum dichloride). Completion of polymerization ofthe A block was confirmed by monitoring the molecular weight atintervals with a gel permeation chromatography (GPC).

Then, polymerization was continued by adding 24 mmol of EOVEconstituting the B block. After completion of polymerization of the Bblock was confirmed by monitoring with GPC, the polymerization wascontinued by adding a toluene solution of 10 mmol of the C blockcomponent. The polymerization reaction was terminated after 20 hours.The termination of the polymerization was achieved by adding a 0.3 mass% ammonia/methanol aqueous solution. The reaction mixture was dilutedwith dichloromethane, and was washed three times with 0.6 M hydrochloricacid and three times with distilled water. The obtained organic phasewas concentrated and dried in an evaporator, then dried under vacuum andwas subjected to repeated dialyses with a cellulose semi-permeatingmembrane and in methanol for eliminating monomer compounds, therebyobtaining a desired triblock polymer. The compound was identified by NMRand GPC, and had Mn=38,300, Mw/Mn=1.34, and a polymerization ratioA:B:C=100:200:30. A polymerization ratio of two monomers in the A blockwas 1:1.

The block polymer obtained above was subjected to a hydrolysis in amixture of dimethylformamide and an aqueous sodium hydroxide solution toobtain a triblock polymer in which the C block was hydrolyzed andconverted into a sodium salt. The compound was identified by NMR andGPC.

It was further neutralized in an aqueous dispersion with 0.1 Nhydrochloric acid to obtain a triblock polymer in which the C componentwas converted into a free carboxylic acid. The compound was identifiedby NMR and GPC.

Example 3

Fifteen parts by mass of the block polymer of the carboxylic acid salttype obtained in the example 1, and 7 parts by mass of oil blue-N(C.I.Solvent Blue-14, manufactured by Aldrich Corp.) were co-dissolved in 150parts by mass of dimethylformamide, and the solution was converted to anaqueous phase by employing 400 parts by mass of distilled water, therebyobtaining an ink composition. It was let to stand at the roomtemperature for 10 days, but the oil blue did not cause separation norprecipitation.

Example 4

Fifteen parts by mass of the block polymer of the carboxylic acid salttype obtained in the example 2, and 7 parts by mass of oil blue-N(C.I.Solvent Blue-14, manufactured by Aldrich Corp.) were co-dissolved in 150parts by mass of dimethylformamide, and the solution was converted to anaqueous phase by employing 400 parts by mass of distilled water, therebyobtaining an ink composition. The viscosity was 0.005 Pa·s (5 cps, 20°C.). It was let to stand at the room temperature for 10 days, but theoil blue did not cause separation nor precipitation.

Example 5

The ink prepared in the example 3 was filled in a printing head of anink jet printer (trade name: BJF800, manufactured by Canon Inc.) and wasused in printing operation. One minute after the printing, a printedportion was rubbed strongly three times with a line marker, but no bluetrailing could be observed and a very satisfactory fixing ability wasconfirmed.

Comparative Example 1

An ink composition was prepared by mixing 2 parts by mass of a blackself-dispersible pigment (trade name: CAB-0-JET300, manufactured byCabot Corp.), 0.5 parts by mass of a surfactant (Nonion E-230,manufactured by NOF Corp.), 5 parts by mass of ethylene glycol and 92.5parts by mass of ion-exchanged water. It had a viscosity of 0.004 Pa·s(4 cps, 20° C.). The ink composition was used in recording operation inthe same manner as in the example 5, and 1 minute after recording, aprinted portion was strongly rubbed once with a line marker whereby ablack trailing was observed.

Example 6

A block polymer having the same A, B and C blocks as in the example 1and a polymerization ratio A:B:C=100:100:30 was prepared in the samemanner as in the example 1. There were obtained Mn=25,300 andMw/Mn=1.39.

Example 7

The dispersion of micelles including the oil-soluble dye, obtained inthe example 3, was brought to a pH value of 3 by addition of 2Nhydrochloric acid, whereby the viscosity of the composition increasedsignificantly to 0.230 Pa·s (230 cps). A printing test was executed onan ordinary paper sprayed with hydrochloric acid, and a printed portionwas rubbed strongly five times with a line marker, but no blue trailingcould be observed and a very satisfactory fixing ability was confirmed.

Example 8

The dispersion of micelles including the oil-soluble dye, obtained inthe example 4, was cooled to 5° C., whereby the viscosity of thecomposition increased significantly to 0.110 Pa·s (110 cps). In theemployed triblock polymer, the B segment was a polymer responsive to atemperature stimulus, and was confirmed by DSC to cause a phasetransition at about 20° C. in an aqueous solution. Such B segment showshydrophobicity and hydrophilicity respectively above and below suchboundary temperature. Consequently, by cooling the dispersion to belowthe boundary temperature which is 20° C., the B segment becomehydrophilic and spreads, thereby inducing a mutual interaction of themicelles and causing an increase in the viscosity. A printing test wasexecuted on an ordinary paper cooled to 5° C., and a printed portion wasrubbed strongly five times with a line marker, but no blue trailingcould be observed and a very satisfactory fixing ability was confirmed.

Comparative Example 2

When a dispersion prepared in the comparative example 1 was cooled to 5°C., the viscosity became 0.008 Pa·s (8 cps) and no increase in theviscosity could be observed. A printing test was executed on an ordinarypaper cooled to 5° C. as in the example 8, and a black trailing could beobserved as in the comparative example 1.

Example 9

<Synthesis of Block Polymer>

Synthesis of a triblock polymer constituted of isobutyl vinyl ether(IBVE: A block), 2-methoxyethyl vinyl ether (MOVE: B-block) and ethyl6-(2-vinyloxy)ethoxycaproate (VEEtPenCOOEt: C block):

The interior of a glass container equipped with a three-way stopcock wasreplaced with nitrogen, and adsorbed water was eliminated by heating at250° C. under a nitrogen flow. After the system was returned to the roomtemperature, 10 mmol of IBVE, 16 mmol of ethyl acetate, 0.05 mmol of1-isobutoxyethyl acetate and 11 ml of toluene were added and thereaction system was cooled. When the temperature in the system reached0° C., polymerization was initiated by adding 0.2 mmol of ethyl aluminumsesquichloride (equimolar mixture of diethyl aluminum chloride and ethylaluminum dichloride). Completion of polymerization of the A block wasconfirmed by monitoring the molecular weight at intervals with a gelpermeation chromatography (GPC).

Then, polymerization was continued by adding 10 mmol of MOVEconstituting the B block. After completion of polymerization of the Bblock was confirmed by monitoring with GPC, the polymerization wascontinued by adding a toluene solution of 10 mmol of the C blockcomponent. The polymerization reaction was terminated after 20 hours.The termination of the polymerization was achieved by adding a 0.3 mass% ammonia/methanol aqueous solution. The reaction mixture was dilutedwith dichloromethane, and was washed three times with 0.6 M hydrochloricacid and three times with distilled water. The obtained organic phasewas concentrated and dried in an evaporator, then dried under vacuum andwas subjected to repeated dialyses with a cellulose semi-permeatingmembrane and in methanol for eliminating monomer compounds, therebyobtaining a desired triblock polymer. The compound was identified by NMRand GPC, and had Mn=46,300, Mw/Mn=1.36, and a polymerization ratioA:B:C=200:200:90.

The block polymer obtained above was subjected to a hydrolysis in amixture of dimethylformamide and an aqueous sodium hydroxide solution toobtain a triblock polymer in which the C block was hydrolyzed andconverted into a sodium salt. The compound was identified by NMR andGPC.

It was further neutralized in an aqueous dispersion with 0.1 Nhydrochloric acid to obtain a triblock polymer in which the C componentwas converted into a free carboxylic acid. The compound was identifiedby NMR and GPC.

Example 10

Synthesis of a triblock polymer constituted of isobutyl vinyl ether andCH₂═CHOCH₂CH₂OPhPh (IBVE-r-VEEtPhPh: A block), 2-methoxyethyl vinylether (MOVE: B-block) and ethyl 6-(2-vinyloxy)ethoxycaproate(VEEtPenCOOEt: C block):

The interior of a glass container equipped with a three-way stopcock wasreplaced with nitrogen, and adsorbed water was eliminated by heating at250° C. under a nitrogen flow. After the system was returned to the roomtemperature, 2.5 mmol of IBVE, 2.5 mmol of VEEtPhPh, 16 mmol of ethylacetate, 0.05 mmol of 1-isobutoxyethyl acetate and 11 ml of toluene wereadded and the reaction system was cooled. When the temperature in thesystem reached 0° C., polymerization was initiated by adding 0.2 mmol ofethyl aluminum sesquichloride (equimolar mixture of diethyl aluminumchloride and ethyl aluminum dichloride). Completion of polymerization ofthe A block was confirmed by monitoring the molecular weight atintervals with a gel permeation chromatography (GPC).

Then, polymerization was continued by adding 10 mmol of MOVEconstituting the B block. After completion of polymerization of the Bblock was confirmed by monitoring with GPC, the polymerization wascontinued by adding 10 mmol of the C block component. The polymerizationreaction was terminated after 24 hours. The termination of thepolymerization was achieved by adding a 0.3 mass % ammonia/methanolaqueous solution. The reaction mixture was diluted with dichloromethane,and was washed three times with 0.6 M hydrochloric acid and three timeswith distilled water. The obtained organic phase was concentrated anddried in an evaporator, then dried under vacuum and was subjected torepeated dialyses with a cellulose semi-permeating membrane and inmethanol for eliminating monomer compounds, thereby obtaining a desiredtriblock polymer. The compound was identified by NMR and GPC, and hadMn=33,600, Mw/Mn=1.38, and a polymerization ratio A:B:C=100:200:80. Apolymerization ratio of two monomers in the A block was 1:1.

The block polymer obtained above was subjected to a hydrolysis in amixture of dimethylformamide and an aqueous sodium hydroxide solution toobtain a triblock polymer in which the C block was hydrolyzed andconverted into a sodium salt. The compound was identified by NMR andGPC.

It was further neutralized in an aqueous dispersion with 0.1 Nhydrochloric acid to obtain a triblock polymer in which the C componentwas converted into a free carboxylic acid. The compound was identifiedby NMR and GPC.

Example 11

Twenty-six parts by mass of the block polymer of the carboxylic acidsalt type obtained in the example 9, and 10 parts by mass of anoil-soluble dye Oil Blue-N (trade name: being the same as above,manufactured by Aldrich Corp.) were co-dissolved in dimethylformamide,and the solution was converted to an aqueous phase by employing 400parts by mass of distilled water, thereby obtaining an ink composition.It was let to stand at the room temperature for 10 days, but the oilblue did not cause separation nor precipitation.

Example 12

Twenty-six parts by mass of the block polymer of the carboxylic acidsalt type obtained in the example 10, and 10 parts by mass of anoil-soluble dye Oil Blue-N (trade name: being the same as above,manufactured by Aldrich Corp.) were co-dissolved in dimethylformamide,and the solution was converted to an aqueous phase by employing 400parts by mass of distilled water, thereby obtaining an ink composition.It was let to stand at the room temperature for 10 days, but the oilblue did not cause separation nor precipitation.

Example 13

The ink prepared in the example 11 was filled in a printing head of anink jet printer (trade name: BJF800, manufactured by Canon Inc.) and wasused in printing operation. One minute after the printing, a printedportion was rubbed strongly three times with a line marker, but no bluetrailing could be observed and a very satisfactory fixing ability wasconfirmed.

Example 14

The dispersion of the example 10 was brought to a pH value of 3 by anaddition of 2N hydrochloric acid, whereby the viscosity of thecomposition increased significantly to 320 cps when observed with DAR100(manufactured by Rheologica Inc.). Prior to the viscosity increase, thecomposition had a viscosity below a detection limit, below 10 cps. Aprinting test in example 13, executed on an ordinary paper sprayed withhydrochloric acid, provided a clear print. A printed portion was rubbedstrongly with a line marker, but no blue trailing could be observed,showing a satisfactory fixing ability and a satisfactory waterresistance.

Comparative Example 3

An ink composition was prepared by mixing 5 parts by mass of a blackself-dispersible pigment (trade name: CAB-0-JET300, manufactured byCabot Corp.), 0.5 parts by mass of a surfactant (Nonion E-230,manufactured by NOF Corp.), 5 parts by mass of ethylene glycol and 89.5parts by mass of ion-exchanged water. The ink composition was used inrecording operation in the same manner as in the example 13, and 1minute after recording, a printed portion was strongly rubbed once witha line marker whereby a black trailing was observed.

Example 15

A triblock polymer of the carboxylic acid salt type was synthesized inthe same manner as in the example 1, except that the monomer of the Asegment in the synthesis of the block polymer of the example 1 wasreplaced by EOVE. Then, as in the example 3, an ink composition wasobtained by dissolving 15 parts by mass of the thus obtained blockpolymer of the carboxylic acid salt type and 5 parts by mass of OilBlue-N(C.I. Solvent Blue-14, manufactured by Aldrich Corp.) in 150 partsby mass of dimethylformamide and executing a conversion into an aqueousphase by employing 400 parts by mass of distilled water. The inkcomposition was let to stand for 10 days at the room temperature, butthe Oil Blue did not show separation nor precipitation. The dispersedcomposition was filled in a printing head of an ink jet printer (tradename: BJF800, manufactured by Canon Inc.) and was used in printingoperation as in the example 5. One minute after the printing, a printedportion was rubbed strongly three times with a line marker, but no bluetrailing could be observed and a very satisfactory fixing ability wasconfirmed. Separately, the dispersed composition was brought to 0° C.thereby changing the EOVE polymerized segment, which was hydrophobic, tothe hydrophilic type and the polymer was molecularly dissolved in asolvent, whereby the Oil Blue dye was separated from the dispersion.Based on measurement of the absorption spectrum of the filtrate in thevisible region and on comparison with the absorption spectrum prior tocooling, it was confirmed that the dye was separated by 99.2% or more.This fact confirmed that the Oil Blue dye was included in the polymer by99.2% or more.

Example 16

Twenty-three parts by mass of the block polymer of the carboxylic acidsalt type obtained in the example 10, and 12 parts by mass of a blackpigment (trade name: MOGUL L, manufactured by Cabot Corp.) weredissolved in dimethylformamide, and then 500 parts by mass of distilledwater was added to the solution followed by filtration using a 2 μmmembrane filter to remove coarse particles, thereby preparing an inkcomposition. After the ink composition was left to stand for 10 days, noprecipitation was observed. The ink composition was filled in a printinghead of an ink jet printer (trade name: BJF800, manufactured by CanonInc.) and was used in printing operation. One minute after the printing,a printed portion was rubbed strongly three times with a line marker,but no black trailing could be observed and a very satisfactory fixingability was confirmed.

1. A polymer-containing composition comprising a block polymer compound,water or an aqueous solvent, and a functional material, wherein theblock polymer compound comprises block segments A, B, and C arranged insuccession, the block segment B is a hydrophilic block segment, theblock segment C is most hydrophilic while the block segment A is mosthydrophobic, the block segment C has an ionic group or an acidic group,and the block segment C is a repeating unit represented by the followinggeneral formula (1):

wherein R⁰ represents —X—(COOH)_(r) or —X—(COO-M)_(r); X represents alinear, branched or cyclic alkylene group with 1 to 20 carbon atoms,—(CH(R⁵)—CH(R⁶)—O)_(p)—(CH₂)_(m)—CH_(3-r)—,—(CH₂)_(m)—(O)_(n)—(CH₂)_(q)—CH_(3-r)— or a structure in which at leastone of methylene groups therein is replaced by a carbonyl group or anaromatic ring structure; r represents 1 or 2; p represents an integerfrom 1 to 18; m represents an integer from 0 to 35; n represents 1 or 0;q represents an integer from 0 to 17; M represents a monovalent orpolyvalent cation; and R⁵ and R⁶, which may be the same or different,each independently represent an alkyl group, wherein the block segment Bis a repeating unit represented by either one of the following formulae:

wherein the block segment A is a repeating unit represented by any ofthe following formulae: (a)

(b)

and wherein when the block segment A is the repeating unit representedby formula (b), the block segment B is the repeating unit represented by


2. The polymer-containing composition according to claim 1, wherein thefunctional material is included in the block polymer compound.
 3. Thepolymer-containing composition according to claim 1, wherein thefunctional material is a colorant.